1. Field of the Invention
The present invention relates to a semi-finished blank for a varifocal lens, to a varifocal lens, and to varifocal eyeglasses, which are used as optical members with which the focal point is varied by application of voltage to a varifocal portion.
2. Description of the Related Art
A semi-finished blank for a varifocal liquid crystal lens is made up of a lower substrate whose front face has a convex bend, an upper substrate having a rear face with a concave bend that is joined opposite this front face, a varifocal portion that is disposed between the upper and lower substrates, and so forth. A thin film, such as a transparent conductive film, is formed on the front of the lower substrate and on the back face of the upper substrate. The refractive index of the varifocal portion can be changed by applying voltage to the liquid crystal material via the transparent conductive film, so this blank can be used as a lens for bifocal eyeglasses (Patent Literature 1).